Glazing Stack with Localized High Index Layers for Low Emissivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermal insulation and solar protection glazings face challenges in achieving low emissivity, high light transmission, and neutral color reflection, particularly when using high refractive index dielectric layers, which are costly and difficult to deposit efficiently, and are not preserved during high-temperature heat treatments.
Innovation Solution
A glass substrate with a stack of thin layers comprising a metallic functional layer and anti-reflective coatings, where high refractive index dielectric layers are strategically placed between the metallic layer and the substrate, optimizing their optical thickness to achieve low emissivity and neutral color reflection, while maintaining performance through heat treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high refractive index dielectric layers are used in anti-reflective coatings, then optical performance (low emissivity, neutral color reflection) is improved, but manufacturing cost and deposition difficulty increase
Solution Approach 1:
The patent applies local quality by positioning high refractive index dielectric layers specifically at strategic locations within the anti-reflective coating stack - namely in contact with or near the metallic functional layer on both sides. This localized placement optimizes optical performance (low emissivity, neutral color reflection) while minimizing the total quantity of difficult-to-deposit high index materials, thereby reducing manufacturing complexity and cost.
2Loss of energy
If high refractive index dielectric layers are used, then emissivity is reduced, but production cost increases due to expensive targets and slower deposition speed
Solution Approach 1:
The patent applies partial action by using high refractive index dielectric layers only where most needed - specifically in contact with or near the metallic functional layer - rather than uniformly throughout the entire anti-reflective coating stack. This partial placement achieves sufficient emissivity reduction while minimizing the total amount of expensive high index material required, thereby lowering production cost and improving deposition efficiency.
3Reliability
If high refractive index dielectric layers are placed on each side of metallic functional layer, then optical characteristics are improved, but deposition time increases and productivity decreases
Solution Approach 1:
The patent optimizes the placement of high refractive index dielectric layers to be in contact with or near the metallic functional layer on both sides, rather than distributing them uniformly throughout the coating stack. This localized strategic placement achieves the required optical characteristics improvement while minimizing the total optical thickness and deposition time, thereby maintaining higher productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a cost-effective, high-selectivity glazing with low emissivity and favorable aesthetics, achieving high light transmission and neutral colors in reflection, while being resistant to heat treatments and deposition inefficiencies.
Implementation Method 1
each anti-reflective coating comprises at least one high refractive index dielectric layer... The total optical thickness of the high refractive index dielectric layer... represents between 30 and 75% of the total optical thickness of this underlying anti-reflective coating
Implementation Method 2
a functional metallic layer with reflection properties in infrared and/or solar radiation... capable of acting on solar radiation and/or infrared radiation of great length wave
Implementation Method 3
a functional metallic layer with reflection properties in infrared and/or solar radiation... capable of acting on solar radiation and/or infrared radiation of great length wave
Implementation Method 4
From an optical point of view, the purpose of these coatings which surround the metallic functional layer is to 'anti-reflect' this metallic functional layer
Data Source
Figure 1~2
AI summary
The invention relates to a glass substrate (10) provided, on a main surface, with a thin film stack comprising a metal functional layer (40), in particular made of silver or a metal alloy containing silver and having infrared or solar radiation reflective properties, and two antireflection coatings (20, 60), said coatings each comprising at least two dielectric layers (22, 24, 26, - 62, 64, 66), said functional layer (40) being placed between both antireflection coatings (20, 60), characterized in that each antireflection coating (20, 60) comprises at least one high refractive index dielectric layer (24, 64) contacting or close to the functional layer (40), that is, 10 nm or less from the functional layer (40).